8-epi PGF2 alpha generation during coronary reperfusion. A potential quantitative marker of oxidant stress in vivo

BACKGROUND: Myocardial reperfusion is believed to be associated with free radical injury. However, indexes of oxidative stress in vivo have been limited by their poor specificity and sensitivity. Isoprostanes are stable products of arachidonic acid formed in a nonenzymatic, free radical-catalyzed manner. We have developed a sensitive and specific assay for one of these compounds, 8-epi prostaglandin (PG) F2 alpha. METHODS AND RESULTS: To address its utility as an index of oxidative stress during coronary reperfusion, we measured urinary levels by gas chromatography/mass spectrometry in a canine model of coronary thrombolysis, in patients with acute myocardial infarction treated with thrombolytic therapy, and in patients after elective coronary artery bypass surgery. Urinary 8-epi PGF2 alpha was unchanged after circumflex artery occlusion in a canine model of coronary thrombolysis (n = 13; 437.2 +/- 56.4 versus 432.7 +/- 55.2 pmol/mmol creatinine) but increased significantly (P < .05) immediately after reperfusion (553.8 +/- 64.7 pmol/mmol). Urinary levels were increased (P < .001) in patients (n = 12) with acute myocardial infarction given lytic therapy (265.8 +/- 40.8 pmol/mmol) compared with age-matched control subjects (n = 20; 91.5 +/- 11.8 pmol/mmol) and patients with stable coronary disease (n = 20; 95.7 +/- 6.3 pmol/mmol). Preoperative levels rose from 113.2 +/- 11.8 to 248.2 +/- 86.3 pmol/mmol at 30 minutes into revascularization to 332.2 +/- 82.6 pmol/mmol by 15 minutes after global myocardial reperfusion (P < .05) and dropped to 181.2 +/- 50.4 pmol/mmol at 30 minutes and 120.2 +/- 9.9 pmol/mmol at 24 hours after bypass surgery (n = 5). Corresponding changes in spin adduct formation, found with electron paramagnetic resonance, were noted in 2 patients. CONCLUSIONS: These data support the hypothesis that free radical generation occurs during myocardial reperfusion. Measurement of isoprostane production may serve as a noninvasive index of oxidative stress.     

Cloning and disruption of the antigenic catalase gene of Aspergillus fumigatus

Aspergillus fumigatus possesses two catalases (described as fast and slow on the basis of their electrophoretic mobility). The slow catalase has been recognized as a diagnostic antigen for aspergillosis in immunocompetent patients. The antigenic catalase has been purified. The enzyme is a tetrameric protein composed of 90-kDa subunits. The corresponding cat1 gene was cloned, and sequencing data show that the cat1 gene codes for a 728-amino-acid polypeptide. A recombinant protein expressed in Pichia pastoris is enzymatically active and has biochemical and antigenic properties that are similar to those of the wild-type catalase. Molecular experiments reveal that CAT1 contains a signal peptide and a propeptide of 15 and 12 amino acid residues, respectively. cat1-disrupted mutants that were unable to produce the slow catalase were as sensitive to H2O2 and polymorphonuclear cells as the wild-type strain. In addition, there was no difference in pathogenicity between the cat1 mutant and its parental cat1+ strain in a murine model of aspergillosis.     

Guidelines for the diagnosis and outpatient management of diabetic peripheral neuropathy

AIMS: This series analyses the results of conservative surgery for large lower pole breast cancers by lumpectomy associated with a bilateral remodelling mammoplasty, in order to avoid residual deformities. METHODS: This retrospective study concerns 50 patients with a lower pole breast cancer treated between 1986 and 1996 by lumpectomy, mammoplasty and irradiation. The contralateral breast was immediately made symmetrical in all cases. The mean tumour size was 32.5 mm. RESULTS: The mean weight of the lumpectomy specimen was 270 g. Resection margins were tumour-free in 90% of cases. The main complication observed was delayed healing, thus postponing post-operative treatment in 6.5% of cases. The median follow-up was 48 months. The 5-year actuarial ipsilateral local recurrence rate was 7% and 5-year actuarial metastasis-free and overall survival rates were 81 and 97%, respectively. Cosmesis was satisfactory in 85% of patients. We observed better results when radiotherapy was performed after rather than prior to surgery (92 vs. 67%: NS). CONCLUSIONS: Performing a bilateral mammoplasty at the time of initial surgery for large breast cancers situated in the lower quadrants of the breast facilitates larger lumpectomies with good cosmetic results.     

Identification of glycoprotein 330 as an endocytic receptor for apolipoprotein J/clusterin

Glycoprotein 330 (gp330) is a member of a family of endocytic receptors related to the low density lipoprotein receptor. gp330 has previously been shown to bind a number of ligands in common with its family member, the low density lipoprotein receptor-related protein (LRP). To identify ligands specific for gp330 and relevant to its localization on epithelia such as in the mammary gland, gp330-Sepharose affinity chromatography was performed. As a result, a 70-kDa protein was selected from human milk and identified by protein sequencing to be apolipoprotein J/clusterin (apoJ). Solid-phase binding assays confirmed that gp330 bound to apoJ with high affinity (Kd = 14.2 nM). Similarly, gp330 bound to apoJ transferred to nitrocellulose after SDS-polyacrylamide gel electrophoresis. LRP, however, showed no binding to apoJ in either type of assay. The binding of gp330 to apoJ could be competitively inhibited with excess apoJ as well as with the gp330 ligands apolipoprotein E, lipoprotein lipase, and the receptor-associated protein, a 39-kDa protein that acts to antagonize binding of all known ligands for gp330 and LRP. Several cultured cell lines that express gp330 and ones that do not express the receptor were examined for their ability to bind and internalize 125I-apoJ. Only cells that expressed gp330 endocytosed and degraded radiolabeled apoJ. Furthermore, F9 cells treated with retinoic acid and dibutyryl cyclic AMP to increase expression levels of gp330 displayed an increased capacity to internalize and degrade apoJ. Cellular internalization and degradation of radiolabeled apoJ could be inhibited with unlabeled apoJ, receptor-associated protein, and gp330 antibodies. The results indicate that gp330 but not LRP can bind to apoJ in vitro and that gp330 expressed by cells can mediate apoJ endocytosis leading to lysosomal degradation.     

Dynamical modelling of an activated sludge system of a petrochemical plant operating at high temperatures.

The Mexican petrochemical industry, Morelos S.A. de C.V., is one of the biggest and more important petroleum industries in Mexico and Latin America. It has an activated sludge system to treat its wastewater flow, which is approximately 7,000 m3/d. The wastewater contains volatile organic carbon substances classified as toxics. The old surface aeration system was changed for fine bubble diffusers; however, one major drawback of the new aeration system is that the temperature in the bioreactor has increased due to the compression of the air, which at the compressor exit reaches 85 degrees C. This effect results in the temperature in the bioreactor attaining 32 degrees C during the fall, whereas in the spring and summer, the bioreactor temperature reaches higher values than 40 degrees C. The high temperatures reduce the microorganism activity and cause a higher volatilisation rate of volatile compounds, among other effects, which affect the performance of the biological treatment. This work was performed to obtain a better modelling of the wastewater treatment from the petrochemical industry. The model describes the effect of the temperature on the performance of the biological treatment. The model was obtained from tests that were carried out in laboratory reactors with 14 L capacity, which were operated at different temperatures (from 30 to 45 degrees C), with the same wastewater and conditions as the actual system.     

Simultaneous sulfide and acetate oxidation under denitrifying conditions using an inverse fluidized bed reactor

BACKGROUND: Simultaneous removal of sulfur, nitrogen and carbon compounds from wastewaters is a commercially important biological process. The objective was to evaluate the influence of the CH₃COO^?/NO₃^? molar ratio on the sulfide oxidation process using an inverse fluidized bed reactor (IFBR). RESULTS: Three molar ratios of CH₃COO^?/NO₃^? (0.85, 0.72 and 0.62) with a constant S^2?/NO₃^? molar ratio of 0.13 were evaluated. At a CH₃COO^?/NO₃^? molar ratio of 0.85, the nitrate, acetate and sulfide removal efficiencies were approximately 100%. The N₂ yield (g N₂ g^?1 NO₃^?‐N consumed) was 0.81. Acetate was mineralized, resulting in a yield of 0.65 g inorganic‐C g^?1 CH₃COO^?‐C consumed. Sulfide was partially oxidized to S⁰, and 71% of the S^2? consumed was recovered as elemental sulfur by a settler installed in the IFBR. At a CH₃COO^?/NO₃^? molar ratio of 0.72, the efficiencies of nitrate, acetate and sulfide consumption were of 100%, with N₂ and inorganic‐C yields of 0.84 and 0.69, respectively. The sulfide was recovered as sulfate instead of S⁰, with a yield of 0.92 g SO₄^2?‐S g^?1 S^2? consumed. CONCLUSIONS: The CH₃COO^?/NO₃^? molar ratio was shown to be an important parameter that can be used to control the fate of sulfide oxidation to either S⁰ or sulfate. In this study, the potential of denitrification for the simultaneous removal of organic matter, sulfide and nitrate from wastewaters was demonstrated, obtaining CO₂, S⁰ and N₂ as the major end products. Copyright © 2008 Society of Chemical Industry     

Nanocrystalline TiO2 photosensitized with natural polymers with enhanced efficiency from 400 to 600 nm

TiO₂ sensitization for solar applications requires not only efficient but also stable and inexpensive sensitizers. Different condensed tannins extracted from bark wastes of tropical wood trees were studied as possible sensitizers of TiO₂. These natural polymers adhere strongly to the TiO₂ even from aqueous solutions. Absorption spectra are presented for 1 mM aqueous sensitizing solutions prepared with lyophilized condensed tannins which absorb light in the visible range. Spectral photocurrent measurements and I–V characterization show that no bias is required for electron injection to the TiO₂ from all studied condensed tannins. Incident photon to current efficiency (IPCE) analysis indicates that surface complexation originates absorption bands with different electron injection efficiencies. These play a dominant role in determining IPCE spectral shape. We propose that surface modification by the sensitizer changes the surface trap density, thereby decreasing recombination losses.